Firstly, how much longer can demand for iPhones grow? The iPhone demand is off-the-charts, and the iPhone 6S’s new features like 3D Touch Dispaly, Force Touch and an improved camera seem compelling enough to keep the momentum going.

Secondly, can Apple TV ever become more than a hobby? After selling 20 million Apple TVs over seven years, it has still been considered as a niche market product.

Thirdly, can the iPad Pro drive the dying tablet sales? iPad sales have fallen for six straight quarters. The downward trend for the iPad follows an overall slump in tablets. Can the 12.9-inch iPad Pro save the moribund tablet market still remained unknown.

Fourthly, is the Watch the next big thing or just a curiosity? Industry analysts say Apple sold about 3 million Apple Watches last quarter. Apple is urging folks to hold off judgment until the holiday season, saying it will be a big seller during the fall and winter. The lastest Apple Watch teamed up with the luxury fashion brand Hermes, implying that its TA is the top of the pyramid consumers.

Fifthly, can Macs ever go mainstream? Apple has lately been among the only companies with growing PC sales, but it is still a long way to go to compete with Microsoft.

Finally, will Apple Music make up for lost iTunes sales? As more folks listen on streaming services, iTunes music downloads have fallen. Consequently, Apple bought Beats for $3 billion and relaunched the Beats Music streaming app as Apple Music. However, according to MusicWatch, only 52 percent of Apple Music customers are still using the service after subscribing to the introductory three-month free trial.

These six challenges should not only worried Time Cook, all the Apple partners in Taiwan had better taken into consideration.